The paper presents issues related to an attempt to recreate the geometry of an involute spur gear with non-standard geometric parameters such as: module m = 4.98 mm, radial clearance factor c* = 0.383, addendum modification y = 0.795, profile shift x = 0.0695, profile angle α = 26.325° and with straight teeth, made in the 6 degree IT, using conventional techniques and measuring instruments. In the process of recreating the geometry of the tested gear, a completely different set of parameters was obtained: m = 5 mm, c* = 0.418, y = 0.81, x = 0.0143, α = 26.806°. The correctness of the reconstructed geometry was assessed by comparing the position of the contour of the involute of the nominal gear with the contour of the involute of the reconstructed gear, establishing that the error value ∆e along the radius leading tangent to the base circle of the restored gear was 0.0054 mm. However, the most important stage of this work is to demonstrate that two involute gears with straight teeth can be identical despite using different geometric parameters in most of them (including, in particular, different modules m and different nominal profile angles α). A formula was derived to calculate the exact value of the profile shift for a new, alternative set of geometric parameters with a different module. A matrix was developed that allows making calculations to derive two identical gears with alternative sets of geometric parameters. Therefore, a proper and valid alternative set of geometric parameters was adopted for the reproduced gear for which the modulus was m = 5 mm, together with c* = 0.380, y = 0.793, x = 0.0325, α = 26.784°. The paper also outlines further research plans.
The main subject of work is a concept bike featuring a non-standard construction. The classic frame has been replaced with a straight beam. Consequently, there is a much greater stress on some of the components of the bike body. Furthermore, the construction of these body components becomes more complex which calls for the employment of the numerical method of stress calculation. The work involved carrying out a strength analysis for several selected components of the bike body utilizing the finite element method (FEM). The primary object of analysis was the wheel rotation mechanism. The result of the analysis allows to develop an optimized construction, allowing to select the most suitable materials and to determine the appropriate and compact dimensions.
Modern machine manufacturers are making the design and technology of their products more and more complicated. This is to protect against a frequently used practice at customers, i.e. making extra parts on your own. This is because entrepreneurs often cannot afford to order expensive original spare parts and - using reverse engineering - prepare working drawings and commission the components to be made in their own machine park or externally from local suppliers. However, the matter is more complex in the case of gears, which so far have been designed on the basis of the selection of standard geometric parameters. A small modification of one or more of these parameters is enough and it becomes very difficult to recreate the geometry of such a gear. This paper presents the issues related to the reverse engineering of a spur involute gear with very non-standard parameters m = 4.98, α = 26.325 °, x = 0.0695, y = 0.795, c* = 0.383. Further metrological steps were proposed that should be taken to correctly identify at least the fact that the test object is not a part produced by standard modular tools (Fellows cutter, Maag rack cutter, worm cutter, etc.). The work also includes short graphical analyzes of the recreated geometry.
Due to the variety of materials used for flat belts of belt conveyors and the further development of material engineering in relation to these belts, the methods of their connection become an increasingly problematic issue. The belts can be connected mainly in three ways: vulcanized (weldable or heat-weldable), glued or mechanically. The latter method is one of the simplest and most universal in terms of the material variety of belts; however, there are many design variations of mechanical fasteners, and each of them has a certain advantage in a narrow group of properties, e.g., the thickness spectrum of a conveyor belt, the minimum diameter of a drive roller or the range of transferable longitudinal loads. The objective of this paper is to analyze the design solutions of commercial mechanical fasteners used mainly for flat rubber-fabric, composite or plastic belts. To fulfill this goal, a preliminary analysis of the stress distribution for an exemplary solid mechanical fastener was carried out in two cases: during ramp-up and during circulating around the roll, followed by a detailed review of commercial solutions available on the market. In addition to determining the current state of knowledge and technology and determining the state of ignorance, special algorithm and design maps have been created, thanks to which the process of selecting the right mechanical fastening will be easier. The overview includes several tables with detailed information on individual connection properties. Additionally, several design aspects were derived, within which individual mechanical connections may differ. This is to enable the generation of customized solutions in the future by proposing an appropriate mathematical model, on the basis of which it will be possible to generate optimal design properties for a given application.
Summary Modeling of complex construction problems for randomly changing technological processes occurs during the production of rubber compounds. Without a good knowledge of the technology of producing rubber compounds, durable and efficient mixers cannot be designed. The conducted industrial research has been shown that the process of mixing the raw materials varies in time and that the forces acting inside the mixer chamber are distributed randomly. During the mixing process of the chemical components, the position of the force changes inside the mixing chamber. The load on the mixer changes over time - as a result of mixing the raw materials and the pressure of the beater. After feeding the raw materials into the mixing chamber, a big concentrated force is reacted on the ram of the mixer, which over time is transformed into several concentrated forces acting simultaneously. Then, as a result of mixing raw materials, temperature and chemical reactions, a pressure acts on the walls of the chamber and the ram of mixer. The conducted research has proved that the most dangerous, from the point of view of the mechanical durability of the mixer, is the first stage of production, in which the beater is subjected to concentrated force. Then, the compactor deforms much more and it can scratch the surface leading to damage to the mixer. The conducted research allows for a much better understanding of the process and thus to carry out a variant simulation of deformations occurring during operation, and thus to improve the durability of the mixer mechanisms.
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